There has been conventionally known an internal combustion engine provided with an intra-cylinder pressure sensor, as disclosed in Patent Literature 1, for example. Further, Patent Literature 1 discloses detecting a deviation amount of the detected pressure characteristic, which occurs due to hysteresis of the intra-cylinder pressure sensor, with respect to the reference pressure characteristic in the cylinder during fuel cut. More specifically, the deviation amount of the detected pressure characteristic with respect to the reference pressure characteristic is detected by comparing the detected pressures in the symmetrical angle positions in the detected pressure characteristic with the top dead center between the compression stroke and the expansion stroke (hereinafter, called the compression top dead center) as the center. According to the art like this, a sensitivity fault of an intra-cylinder pressure sensor can be diagnosed from the deviation amount that is detected.